Abstract

We show that with increasing magnitude of current , insulator-metal (I-M) transition in becomes discontinuous and shifts down in temperature, which is accompanied by an abrupt decrease in temperature of the sample while cooling. The I-M transition exhibits a hysteresis while warming. A magnetic field of results in −99% magnetoresistance for compared to −32% for . Our results underscore the importance of inhomogeneous Joule heating that leads to coexistence of the high temperatureparamagnetic phase with the low temperatureferromagnetic phase over a wide temperature range.